Film fill plastic media and attached biofilm growth I Wastewater treatment
Biological processes in wastewater treatment can be classified into two main categories: suspended growth and attached growth/ biofilm processes. In suspended growth processes the microorganisms responsible for wastewater treatment are maintained in liquid suspension by appropriate mixing and aeration. The most common suspended growth process is activated sludge. Instead in the attached growth process, the […]
Oxygen transfer rate in Wastewater treatment – calculation example
Before we can calculate the oxygen transfer rate, we have to determine our oxygen demand. Depending on the wastewater treatment target different factors must be considered to calculate the actual oxygen requirement (AOR). Design flows and loads: Water influents are not consistent and vary between daily minimum, average and peak flows. Design guidelines recommend dividing […]
Surface aerators and submersible aeration equipment for wastewater treatment
The activated sludge process requires certain types of microorganisms to break down organic matter in wastewater. As any other living organism, the microorganisms need energy to reproduce. When breaking down organic matter or oxidizing ammonium (NH4+) to Nitrite (NO2-) energy in the form of ATP for microorganism reproduction is released. However, both conversions need oxygen. […]
Activated sludge process – Upgrade with IFAS
After explaining how the activated sludge process works in part 1 we are now taking a closer look on how to increase the wastewater treatment capacity of ASP with IFAS systems. IFAS stands for integrated fixed film activated sludge and describes the combination of fill media attached growth systems with the activated sludge process. The […]
Activated sludge process and IFAS – Design rules + guideline
Activated sludge is worldwide the most used suspended growth process in wastewater treatment. The treatment process can include different steps, but most commonly are: Screening and grit removal to filter out debris Primary clarifier for particle sedimentation Biological treatment with activated sludge consisting of an aeration basin, secondary clarifier and recycle stream Disinfection for […]
Flocculation and coagulation – How to form particle flocs and settle them down
Flocculation and coagulation are fundamental for wastewater treatment and were already used by the ancient Egyptians in 1,300 BC. This sample of muddy looking water from a paper mill has a very high turbidity due to the presence of many suspended particles. Adding flocculants will cause that small particles clump together to bigger flocs that […]
History of wastewater treatment – from Hippocratic sleeve to activated sludge
Nowadays wastewater treatment plants are large, complex facilities that use multiple technologies to remove up to 99% of all pollutants in wastewater. Our standards for clean water are continuously rising and not one day passes by without new innovations for wastewater treatment. But wastewater treatment was not always this advanced. So, let’s have a look […]
Wastewater treatment process description
Wastewater Treatment Plant Wastewater treatment plant (WWTP) are facilities created to remove contaminants from effluents. These facilities can be found in industrial plants, treating the industrial wastewater generated in the production process, or they can be found as part of the municipal wastewater treatment process attending to the sewage produced in water, commerce and small […]